Answer:
Metabolism; catabolic.
Step-by-step explanation:
Living system can be defined as the internal systems of organisms and how materials circulate within organisms.
Generally, these living systems are self-organized life forms and are known to be very much interactive with their surroundings or environment. Also, living systems are dependent on the flow of information, matter and energy at various levels.
Some examples of living systems in organisms are respiratory system, nervous system, digestive system, and circulatory system.
Additionally, living systems comprises of the following components; cells, organs, muscle, tissues, blood, etc., which are typically used for carrying out various bodily functions such as respiration, digestion, metabolism, etc.
Metabolism refers to the set of chemical processes carried out by an organism in order to sustain life. Digestion is a form of catabolic activity because it involves the breaking down of food into smaller sizes that can be absorbed as nutrients by the body while releasing energy through the process.